Big Boilers: Definition, Applications, and ZOZEN’s Solutions

1.What are big boilers?

In the boiler industry, the phrase big boilers refers primarily to boilers with large steam capacity (high evaporation rate), not simply large weight or physical size. Big boilers are defined by their steam output—typically measured in tons per hour (t/h). While thresholds vary by market and application, boilers with steam capacities above about 10 t/h are commonly considered mid-to-large; industrially significant big boilers generally start at 20 t/h and extend to 100 t/h and beyond. For practical purposes, many users and manufacturers classify big boilers as units delivering 20 t/h or more of steam, since systems at this scale require dedicated feedwater systems, larger burners or fuel handling, and extensive safety and control measures.

Big boilers are chosen where sustained, high-volume steam or thermal output is essential. Choosing big boilers is driven by economy of scale: higher-capacity boilers often have lower specific fuel consumption per ton of steam, simplified centralization of utilities, and improved control over steam quality for large processes. However, big boilers require higher capital investment, more stringent regulatory compliance, and greater site infrastructure (fuel supply, water treatment, emissions control).

2. ZOZEN’s representative big boilers

ZOZEN Boiler offers a range of big boilers to meet diverse industrial steam demands. Below are three representative series often specified where big boilers are required.

• SZS series oil/gas-fired steam boilers

The SZS series are large-capacity, two-drum, once-through or natural circulation boilers designed for oil and gas firing. They are widely applied where reliable, clean-burning steam is required at high capacities and pressures.

Features: Vertical economizer, optimized water-wall arrangement, efficient convective heating surfaces, and advanced burner systems for low NOx emissions.

Typical capacities and parameters: Steam capacities range from 2 t/h -110 t/h, thermal efficiency can be over 98%, with design pressures from low to high (customizable to application), making the SZS series a core offering when big boilers are needed for thermal power, district heating, and large industrial plants.

I. Case Demand:

1. 35 t/h gas steam boiler

2. There is a lifting restriction on the dock of Nicaragua, so the transportation weight needs to be reduced.

3. The boiler is used for the steam and heat supply of Nicaragua textile production base.

4. Visit the production base of ZOZEN Boiler.

II. User profile:

Texhong Textile Group Limited was founded in 1997. Now it has developed into one of the largest core cotton textile suppliers in the world. Headquartered in Shanghai, Texhong Textile Group has many textile production bases in China, also, it sets up large industrial bases in Cambodia, Turkey, Mexico and Nicaragua.

III. Solutions:

The 35 t/h gas steam boiler purchased by Texhong Textile Group is used in Nicaraguan industrial base to supply steam and heat for the production base. The customer pointed out that the lifting conditions of the dock in Nicaragua were very limited. In response to this demand, ZOZEN Boiler specially customized the boiler transportation plan for the user, which removed the refractory materials and outer packaging of the boiler body and transported separately, to reduce the weight. At the same time, ZOZEN Boiler sent engineers to Nicaragua project site to assist installation work.

• DZL series biomass-fired steam boilers

The DZL series are three-drum biomass-fired steam boilers engineered to handle large-scale biomass combustion. As big boilers, DZL units are used where renewable solid fuels (wood chips, pellets, agricultural residues) can supply continuous high steam loads.

Features: Robust three-drum water-tube construction, efficient flue gas flow, chain grate or other suitable fuel-feeding grates, and options for anti-clinker designs and enhanced ash handling. DZL big boilers can be equipped with combustion controls and emission-treatment systems to meet environmental standards.

Typical capacities and parameters: DZL big boilers are available in ranges that cover the big boilers segment (10 t/h-40 t/h), thermal efficiency is over 88%, with design pressure and heating surface tailored to customer needs for pulp & paper, biomass power plants, and large industrial steam loads seeking renewable-fuel solutions.

Since the establishment of General Rubber Thailand Co., Ltd. in 2019, it has not only successfully achieved an annual production capacity of 7.3 million sets of various types of tires, but also through technological innovation and capacity expansion, the annual production capacity has been increased to 16 million sets of semi-steel radial tires and 1.3 million sets of all-steel radial tires.

Steam boilers have a wide range of applications in the rubber and tire industry, including key production processes such as vulcanization, drying and curing, and thermal energy supply. The 40-ton DZL series biomass steam boiler from ZOZEN has provided strong support for the production of General Rubber Thailand Co., Ltd.

Environmental Friendliness: The use of biomass fuel has significantly reduced carbon emissions in the production process, aligning with global environmental protection trends.

Efficiency: With a thermal efficiency of up to 87.5%, it ensures the efficient use of energy and reduces production costs.

The cooperation between ZOZEN and General Rubber Thailand Co., Ltd. this time is not only an important upgrade for the Thai rubber industry but also another successful case of ZOZEN Boiler in the overseas market.

• DHL series coal-fired boilers

The DHL series comprises large-scale coal-fired boilers for industries and plants dependent on coal as a primary fuel. These big boilers are designed for continuous high-duty operation with robust fuel handling and ash discharge systems.

Features: Optimized combustion chambers, mechanical grates or pulverized fuel options depending on configuration, heavy-duty refractory and wear-resistant materials, and comprehensive emission control options (electrostatic precipitators, baghouses, desulfurization systems).

Typical capacities and parameters: DHL series covers the big boilers category with capacities from 20 t/h-75 t/h, thermal efficiency ≥ 82%, suitable for sugar mills, large industrial complexes, and power generation where coal remains a primary fuel source.

PT Angels Products has been actively engaged in the crystallized sugar refining industry since 2003. Now, PT Angels Products is one of the biggest companies in the field of crystal sugar refinery industrial in the province of Banten. In crystallized sugar refining, decolorization, evaporation, crystallization and drying are important processes, which need to consume a large number of steam. Moreover, food industry has high requirements for sanitation, a lot of steam needs to be used for disinfection and sterilization. Providing high quality and hygienic products is this company’s core value. Therefore, they have strict requirements of the steam quantity and quality. After visiting and comparing, PT Angels Products chose ZOZEN DHL series coal-fired steam boilers, which are designed with stable combustion, sufficient output and high-quality steam. But field-assembled boilers have high requirements for on-site installation. Then, ZOZEN cooperated with local agent and succeeded in completing the installation of the boiler, which can meet the company’s demand.

3. ZOZEN as a big boilers manufacture — strengths and service system

ZOZEN has established itself as a major provider in the big boilers market through comprehensive manufacturing capacity, deep engineering expertise and a global service network. As a big boilers manufacture, ZOZEN’s strengths include:

Large-scale manufacturing capability: ZOZEN’s fabrication plants are equipped with CNC machining, automated welding systems and heavy plate rolling equipment to produce pressure parts and assemblies for big boilers reliably and repeatably. This capacity enables delivery of large steam units on competitive timelines.

Engineering and customization: As an experienced big boilers manufacture, ZOZEN delivers tailored engineering—sizing steam drums, economizers, superheaters and furnace arrangements to meet process requirements, fuel characteristics and site constraints. Design flexibility allows optimization for efficiency, emissions and maintenance.

R&D and testing: ZOZEN invests in research to improve heat transfer, reduce fouling and extend component life for big boilers. Performance testing, hydrostatic tests and factory acceptance testing validate each unit’s readiness before shipment.

Quality assurance and certification: Acting as a reputable big boilers manufacture, ZOZEN follows strict QA/QC protocols and holds relevant domestic and international certifications for pressure vessel manufacture and environmental management, ensuring compliance across target markets.

Turnkey project delivery: ZOZEN provides full project support—from feasibility studies and detailed engineering to manufacturing, on-site installation supervision, commissioning and operator training. This turnkey approach simplifies project execution for customers procuring big boilers.

After-sales and lifecycle services: ZOZEN maintains a global network of service engineers and spare-parts warehouses to support big boilers in operation. Service offerings include preventive maintenance contracts, spare-part kits for critical components, rapid-response field service and remote monitoring systems that support condition-based maintenance.

Emissions and compliance support: For big boilers where regulatory compliance is critical, ZOZEN offers flue gas treatment packages, low-NOx burners and tailored combustion controls to meet local environmental standards while maintaining plant efficiency.

Conclusion

Big boilers play a central role wherever high, continuous steam demand is required.  ZOZEN’s SZS oil/gas boilers, DZL biomass boilers and DHL coal boilers represent the company’s core big boilers offerings, backed by strong manufacturing, engineering and service capabilities. As a global big boilers manufacture, ZOZEN can provide tailored, turnkey solutions and lifecycle support to meet demanding industrial steam needs.